This invention relates to organic orthocarbonates and more particularly to organic polynitro orthocarbonates.
In the early 1950's, M. E. Hill and coworkers at the Naval Ordnance Laboratory found that certain nitroalcohols would react with carbon tetrachloride in the presence of anhydrous ferric chloride to yield ##STR4## symmetrical orthocarbonates. (e.g., see U.S. Pat. No. 3,306,939 entitled "Orthoesters of 2,2,2-Trinitroethanol," which issued to Marion E. Hill on Feb. 28, 1967.) However, the reaction is of very limited synthetic value for energetic orthocarbonates as only three nitroalcohols (2-fluoro-2,2-dinitroethanol, 2,2,2-trinitroethanol and 2,2-dinitropropane-1,3-diol) have been successfully used. With other nitroalcohols side reactions predominate and the principal product is the carbonate. Another drawback to Hill's method is that only symmetrical and no "mixed" orthocarbonates can be prepared. In a previous patent application filed by William H. Gilligan, 2:2 mixed fluoro-, nitro- and fluoronitroalkyl orthocarbonates were disclosed. Also, U.S. patent application Ser. No. 476,713, entitled "1:3 mixed polynitroethyl orthocarbonates from Tris(2-fluoro-2,2-dinitroethyl) Methyl Trichloromethyl Disulfide," filed by Michael E. Sitzmann and William H. Gilligan simultaneously with the present application Feb. 18, 1983, discloses 1:3 mixed orthocarbonates of the formula [CF(NO.sub.2).sub.2 CH.sub.2 O].sub.3 --C--OR wherein R is a nitroalkyl group which is not CF(NO.sub.2).sub.2 CH.sub.2 --. The method as described is limited to the ##STR5## preparation of a symmetrical trialkoxymethyl trichloromethyl disulfide in which all the alkoxy groups (RO) are identical. The symmetrical disulfide is chlorinated and treated with a second type of alcohol (R'OH) to give the 1:3 "mixed" orthocarbonate. 1:1:2 "mixed" orthocarbonates cannot be prepared by the method. In addition, the method as described is applicable only for 1:3 "mixed" orthocarbonates where ROH does not readily undergo reverse Henry reaction and thus is stable to the basic reaction conditions under which the symmetrical disulfide is formed.